Laser gradient setting device

ABSTRACT

A laser gradient setting device, having such an arrangement that a reference laser beam with a gradient is emitted and a reference laser beam in vertical direction is emitted, whereby the laser gradient setting device can be easily positioned by the reference laser beam in vertical direction by a single worker.

BACKGROUND OF THE INVENTION

The present invention relates to a laser gradient setting device forsetting reference lines in civil engineering works.

In civil engineering works, it is necessary to have a horizontalreference line or a reference line tilted at a given angle with respectto horizontal line. A laser gradient setting device is used for settingsuch reference lines.

For example, in case concrete pipes are laid for sewage construction,the pipes must be laid without bending and must be tilted at a givenangle.

As typical working processes to bury and lay concrete pipes, and so onin soil, there are the working processes to excavate the ground, to layconcrete pipes one after another into the excavated ditch, and to burythem.

For each given linear section, the ground is excavated to a depth deeperthan the depth where concrete pipes are to be laid, and concrete pipesare laid on a temporary base at the bottom of the ditch.

These concrete pipes are used as a flow passage for city water, sewageor other liquid, and these are laid at a given inclination and withoutbending. If the buried concrete pipes are twisted or turned upward,downward, leftward or rightward, the liquid is stagnated, stopped orleaks out into soil, thus being unable to fulfill the function as a flowpassage. Therefore, a proper reference line must be set when concretepipes are to be installed.

A laser beam is suitable for providing such a reference line because ithas not become slack (as thread does when it is used over a longdistance) and because it causes no disturbance during work and it is notcut off due to interference with concrete pipe or working personnel.

The laser gradient setting device is used for setting a reference linewhen concrete pipes are installed.

Description is now given of a conventional type laser gradient settingdevice in connection with FIGS. 5 and 6.

A conventional type laser gradient setting device 1 in horizontalinstallment emits a laser beam, which provides a reference line inhorizontal direction. If the laser beam is aligned with horizontal line,it provides a horizontal reference line. If the laser beam is tilted ata given angle, it gives a reference line with a gradient.

For each given linear section, a vertical hole 3 deeper than the depthat which the concrete pipe is to be laid is excavated at a startingpoint to bury the concrete pipe 2, and a burying ditch 4 continuous tothe vertical hole 3 excavated at a depth deeper than the depth where theconcrete pipe is laid. The laser gradient setting device 1 is installedin the vertical hole 3. A laser beam is emitted at a gradient θ, and areference laser beam L is provided. The concrete pipe 2 is laid in theburying ditch 4 via a temporary base 5 in such manner that its axiscorresponds with the reference laser beam L.

When the axis of the concrete pipe 2 corresponds with the referencelaser beam L, the concrete pipe 2 is buried by filling the burying ditch4.

The laser gradient setting device 1 must be installed accurately inhorizontal position when it is initially installed. In the past, it hasbeen customary to install the laser gradient setting device 1 inhorizontal position as follows: A support 6 is provided above thevertical hole 3, and a transit 7 is placed on the support 6. A plumb bob8 is suspended from the transit 7 to set a known point 10. Further, thelaser gradient setting device is installed in the vertical hole 3, andthe plumb bob 8 is aligned with the center of the laser gradient settingdevice. Then, the plumb bob 9 is suspended from the laser gradientsetting device 1 to align the plumb bob 9 with the known point 10.

In the conventional positioning method to use the plumb bob, there mustbe two workers to position the plumb bob, to stop swinging of the plumbbob and to adjust thread length, and adjustment must be repeated inorder to accurately align the plumb bob from the transit and the plumbbob from the laser gradient setting device with each reference point.This means low working efficiency and very complicated workingprocedure. The above adjustment must be repeated when deviation occursdue to vibration caused by passing vehicles during work or when the workis resumed after temporary interruption, or when regular checking isperformed. Thus, much time is required for such adjustment.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a laser gradientsetting device, which can be easily positioned by a single worker. Toattain this object, the laser gradient setting device of the presentinvention emits a reference laser beam in vertical direction in additionto the emission of a reference laser beam at a gradient, and theposition of the laser gradient setting device is determined by thevertical reference laser beam.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an embodiment of the present invention;

FIG. 2 is a cross-sectional elevation of the embodiment;

FIG. 3 is a cross-sectional front view of the embodiment;

FIG. 4 is a control block diagram of the embodiment;

FIG. 5 is a schematic side view of an embodiment of a conventional typedevice; and

FIG. 6 is a schematic front view of the embodiment of the conventionaltype device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In the following, description will be given of an embodiment of thepresent invention, referring to the drawings.

In FIG. 1, components which are the same as those in FIG. 5 are referredto by the same symbol.

A laser gradient setting device 11 emits a laser beam 12 in verticaldirection in addition to the beam in horizontal direction. By aligningthe downward laser beam 12 with the known point 10 and by aligning theupward laser beam 12 with the reference point of the transit 7, thelaser gradient setting device 11 can be easily positioned.

Instead of aligning the laser beam 12 with the reference point of thetransit 7, a target 13 may be set at a reference position and the laserbeam 12 may be aligned with the target 13.

Next, the laser gradient setting device 11 will be described, referringto FIG. 2 and FIG. 3.

In an external frame 14 in box shape, a suspension frame 15 with twoplate arms hanging parallel downward is provided, and a pair ofspherical seats 16 having shaft center in horizontal direction areplaced face-to-face to each other inside the arms of the suspensionframe 15.

On each side of a reference laser beam emitter 17, a spherical shaft 18protrudes. By engaging the spherical shaft 18 with the spherical seat16, the reference laser beam emitter 17 can be rotatably mounted intriaxial direction with respect to the suspension frame 15.

On the spherical shaft 18, a spherical surface to engage with thespherical seat 16 is formed at its forward end, and a cylindricalportion is formed at the base. On the cylindrical portion, a rockingframe 19 in concave shape with its lower end open is rotatably mounted.From the spherical surface of the spherical shaft 18, pins 20 and 21protrude in two horizontal directions.

A left-right rotation drive unit 22 is provided on the pin 20 of thesuspension frame 15, and a twist drive unit 23 is provided on the pin21. From rear end surface of the reference laser beam emitter 17, a pin24 aligned with the reference laser beam L protrudes, and an elevationdrive unit 25 is provided on the pin 24.

The left-right rotation drive unit 22 comprises a gear box 26 fixed onthe suspension frame 15, a guide shaft 27 provided in horizontaldirection from the gear box 26, a screw shaft 28, a slider 29 screwedwith the screw shaft 28 and slidably engaged with the guide shaft 27,and a left-right adjusting motor 30 for rotating the screw shaft 28 viathe gear box 26. On the slider 29, an engaging pin 31 slidably engagedwith the pin 20 is mounted, and the pin 20 is pushed rightward in FIG. 2by a spring 32 so that the pin 20 is permanently in contact with theengaging pin 31.

When the left-right adjusting motor 30 is rotated, the screw shaft 28 isrotated, and the slider 29 is displaced in horizontal direction. Thehorizontal displacement of the slider 29 is transmitted to the pin 20via the engaging pin 31, thus rotating the reference laser beam emitter17 integrally with the rocking frame 19 in left and right directions.

The twist drive unit 23 comprises a gear box 33 fixed on the suspensionframe 15, a guide shaft 34 arranged vertically from the gear box 33, ascrew shaft 35 (not shown), a slider 39 screwed with the screw shaft 35and slidably engaged with the guide shaft 34, and a twist driving motor36 for rotating the screw shaft 35 via the gear box 33. On the slider39, an engaging pin 37 slidably engaged with the pin 21 is mounted, andthe pin 21 is pushed downward in FIG. 3 by a spring 38 so that the pin21 is permanently in contact with the engaging pin 37.

When the twist driving motor 36 is rotated, the screw shaft 35 rotatedand the slider 39 is displaced in vertical direction. The verticaldisplacement of the slider 39 is transmitted to the pin 21 via theengaging pin 37, and the reference laser beam emitter 17 is twistedintegrally with the rocking frame 19.

The elevation drive unit 25 comprises a gear box 40 fixed on theexternal frame 14 via a bracket 67, a guide shaft 41 arranged verticallyfrom the gear box 40, a screw shaft 42 (not shown), a slider 43 screwedwith the screw shaft 42 and slidably engaged with the guide shaft 41,and an elevation driving motor 44 for rotating the screw shaft 42 viathe gear box 40. On the slider 43, an engaging pin 45 slidably engagedwith the pin 24 is mounted, and the pin 24 is pushed downward in FIG. 2by a spring 68 so that the pin 24 is permanently in contact with theengaging pin 45.

When the elevation driving motor 44 is rotated, the screw shaft 42 isrotated, and the slider 43 is displaced in vertical direction. Thevertical direction of the slider 43 is transmitted to the pin 24 via theengaging pin 45, and the reference laser beam emitter 17 is tiltedintegrally with the rocking frame 19.

On the rear end of the rocking frame 19, a pin 46 extending in parallelto the pin 20 is mounted. Via the pin 46, an angle setting unit 47 forrelatively rotating the reference laser beam emitter 17 and the rockingframe 19 is mounted on a side of the reference laser beam emitter 17.

The angle setting unit 47 comprises a gear box 48 fixed on a side of thereference laser beam emitter 17, a guide shaft 49 arranged verticallyfrom the gear box 48, a screw shaft 50, a slider 51 screwed with thescrew shaft 50 and slidably engaged with the guide shaft 49, and anangle setting motor 52 for rotating the screw shaft 50 via the gear box48. The angle setting motor 52 is provided with an encoder 69 (to bedescribed later). An engaging pin 53 is mounted on the solder 51. Thepin 53 is slidably engaged with the pin 46. The pin 46 is pusheddownward in FIG. 2 by a spring 54 so that the pin 46 is permanently incontact with the engaging pin 53.

When the angle setting motor 52 is rotated, the screw shaft 50 rotated,and the slider 51 is displaced in vertical direction. The verticaldisplacement of the slider 51 is transmitted to the pin 46 via theengaging pin 53, and the rocking frame 19 is tilted with respect to thereference laser beam emitter 17.

On lower end of the rocking frame 19, a vertical beam emitting unit 55is provided.

Description will be given now on the vertical beam emitting unit 55.

A laser beam emitter 56 is arranged on one of opposing vertical walls ofthe rocking frame 19. On the other of the vertical inner walls, areflection mirror 57 is provided face-to-face to the laser beam emitter56. A beam splitter 58 is arranged between the reflection mirror 57 andthe laser beam emitter 56, and the laser beam emitted from the laserbeam emitter 56 is split and reflected to transmission light and laserbeam 12, which passes through the center of rotation of the referencelaser beam emitter 17 (center of spherical surface of the sphericalshaft 18).

On the rocking frame 19, on the suspension frame 15 and on upper andlower surfaces of the external frame 14, through-holes 59, 60, 61 and 62for passing the laser beam 12 are provided. On upper surface of therocking frame 19, a tilt sensor 63 in parallel to the pin 20 and a tiltsensor 64 perpendicular to the tilt sensor 63 are mounted. On the frontsurface of the external frame 14, a through-hole 65 for passing thereference laser beam L is provided, and support legs 66 are attached onlower surface of the external frame 14. The support legs 66 fulfilladjusting function, performing coarse adjustment for horizontalpositioning of the external frame 14.

The left-right adjusting motor 30 of the left-right rotation drive unit22 is driven by a left-right adjusting controller 71, the twist drivingmotor 36 of the twist drive unit 23 is driven by a twist controller 72,the elevation driving motor 44 of the elevation drive unit 25 is drivenby an elevation controller 73, and the angle setting motor 52 of theangle setting unit 47 is driven by an angle controller 74. Rotationangle signal from an encoder 69 is inputted to the angle controller 74.

The left-right adjustment controller 71, the twist controller 72, theelevation controller 73, and the angle controller 74 are controlled by acontrol unit 70 respectively. To the control unit 70, detection signalsfrom the tilt sensor 63 and the tilt sensor 64 are inputted, and acontrol panel 75 is connected to the control unit 70.

In the following, description will be given the operation.

First, the laser gradient setting device 11 is installed in the verticalhole 3, and coarse horizontal adjustment is performed by the supportlegs 66. The control unit 70 is started by operating the switches on theoperation panel 75.

The angle setting motor 52 is driven, and mechanical reference positionof the reference laser beam emitter 17 and the rocking frame 19 areadjusted, i.e. adjustment is made in such manner that the plane wherethe tilt sensor 63 and the tilt sensor 64 are mounted is aligned inparallel to optical axis of laser beam of the reference laser beamemitter 17.

Next, based on the detection results of the tilt sensors 63 and the tiltsensor 64, control command is issued to the left-right adjustingcontroller 71, the twist controller 72, and the elevation controller 73in order to turn the detection results of the tilt sensor 63 and thetilt sensor 64 to zero, i.e. to set the plane where the tilt sensor 63and the tilt sensor 64 are mounted in horizontal direction. By thiscontrol command, the left-right adjusting controller 71, the twistcontroller 72, and the elevation controller 73 drive the left-rightadjusting motor 30, the twist driving motor 36 and the elevation drivingmotor 44 respectively.

When the tilt sensors 63 and 64 are turned to horizontal condition, thereference laser beam L emitted from the reference laser beam emitter 17is directed in horizontal direction, and the laser beam 12 turned invertical direction by the beam splitter 58 is directed in verticaldirection.

The horizontal position of the laser gradient setting device 11 isadjusted to direct the laser beam 12 in such manner that the known point10 is aligned with the reference point of the transit 7 or the target 13(see FIG. 1). The adjustment of the position of the laser gradientsetting device 11 by the laser beam 12 can be performed by adjusting theposture of the laser gradient setting device 11 itself, and this can becarried out by a single worker.

In case it is desired to tilt the reference laser beam L, gradient isset and inputted to the control unit 70 from the operation panel 75. Thecontrol unit 70 issues drive command to the angle controller 74, and theangle controller 74 inputs driving pulse corresponding to the drivingcommand to the angle setting motor 52. The angle setting motor 52 isrotated in proportion to the number of the driving pulses. Actual amountof rotation is detected by the encoder 69, and the amount of rotation ofthe angle setting motor 52 is monitored. Thus, only the rocking frame 19is tilted.

When tilting operation of the rocking frame 19 is completed, completionsignal is inputted to the control unit 70, and control command is issuedto the left-right adjusting controller 71, the twist controller 72, andthe elevation controller 73 to turn the rocking frame 19 in horizontalcondition.

The operation to turn the rocking frame 19 in horizontal condition isthe same as described above, and detailed description is not given here.

When the rocking frame 19 is turned in horizontal condition again, thereference laser beam L emitted from the reference laser beam emitter 17is set at the desired gradient.

By aligning with the reference laser beam L, it is possible to lay theconcrete pipe 2 at the desired gradient and without bending.

In the above embodiment, the laser beam emitter 56 is separatelyfurnished to emit the laser beam 12, while the reference laser beam Lemitted from the reference laser beam emitter 17 may be split and may beused as the laser beam 12. As the beam splitting means, a half-mirrormay be used instead of the beam splitter.

What we claim are:
 1. A laser gradient setting device, comprising areference laser beam emitter for emitting a reference laser beam with agradient, a supporting means for rotatably supporting the referencelaser beam emitter by spherical bearings, and a laser beam irradiatingmeans for emitting a laser beam in a vertical direction.
 2. A lasergradient setting device according to claim 1, comprising said referencelaser beam emitter having a pair of spherical bearings and rotatablysupported in triaxial directions via said spherical bearings, and arocking frame pivotable on a center line of said spherical bearings,wherein said rocking frame is provided with a beam splitting meansarranged on an optical axis passing through the center of rotation ofsaid reference laser beam emitter, said laser beam irradiating meansarranged on one side of the beam splitting means, and a reference mirrorarranged on the other side of said beam splitting means.
 3. A lasergradient setting device according to claim 1, comprising said referencelaser beam emitter having a pair of spherical bearings and rotatablysupported in triaxial directions via said spherical bearings, and a beamsplitting means, wherein said beam splitting means is arranged on anoptical path of the reference laser beam, thereby splitting thereference laser beam in vertical direction so that an optical axis ofthe split beam passes through the center of rotation of the referencelaser beam emitter.
 4. A laser gradient setting device according to oneof claims 1 to 3, comprising said reference laser beam emitter having oneach side a shaft having a cylindrical portion at the base end and aspherical surface at forward end and rotatably supported in triaxialdirections via said spherical surface at forward end of the shaft, arocking frame rotatably supported on the cylindrical portion of theshaft, a first and a second pins protruding from and aligned with anaxial center of the shaft, a third pin protruding from and aligned withan optical axis of said reference laser beam emitter, a fourth pinprotruding from said rocking frame, a left-right rotation drive unit fordisplacing the first pin in a horizontal direction, a twist drive unitfor displacing the second pin in a vertical direction, an elevationdrive unit for displacing the third pin in a vertical direction, and anangle setting unit for displacing the fourth pin in a verticaldirection.
 5. A laser gradient setting device according to claim 4,wherein the first to the fourth pins are rod-like members with circularcross-section, and the members attached to and displacing these pins arerod-like members having circular cross-section.
 6. A laser gradientsetting device according to claim 1, comprising said reference laserbeam emitter having a pair of spherical bearings and rotatably supportedin triaxial directions via said spherical bearings, and a rocking framepivotable on a center line of said spherical bearings, a laser beamirradiating means arranged on said rocking frame, and driving means forrotating said reference laser beam emitter and directing said laser beamirradiating means to a vertical direction.